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4. Intra-layer structures (rank 1) – since
2002.
·Description. Usual methods of strain-analysis used for
intra-layer deformation study in specimens. Additional theoretic method is
the model of multilayer folds formation which include the calculation of
ellipses of deformation for hinge section (Fig. 1, into competent and
incompetent layers) and for flank section (the same layers, total - 4
ellipses). This model was used for study of two folds of Caucasus
(N18 and N20, fig. 2, 3), their specimens were
studied in strain aspect also. A good concordance between natural fold
shapes (table, points 1, 4) and model fold shapes (points 6,7) also as
strains natural (points 12, 13) and models (9, 10) have been found. Total
shortening values of models (point 8) were rather different with strain in
specimens. It means that the model (Fig.1) allows us to spread correctly the
strain analysis data to volume larger then specimens only, based on total
fold shortening of model (point 8).
Some information regarding this item has
described in PhD thesis (Rus) by Vyacheslav Voitenko. Details.
·Publications. (the same as in point
4 lower) The first publication of theoretic model was in (Yakovlev “Investigation of the processes…”, 2002 ã. Text: 319-320, picture 319; PDF -R, N 12 in List-En); the program see in folder SOFT.
The first application of method as comparison of model data with natural
one was published in (Yakovlev, Voitenko, at al. “Regarding ratio of shortening
deformations...”, 2003 ã. PDF-R, see Full List).
·Materials. (the same as in point 6 of Guid
lower) The program code (*.exe + explanation + test examples for study) may
be send after your inquiry using e-mail. If you have difficulties in
strain-analysis study, our expert Vyacheslav Voitenko may assistant you. Let me know about your interest by e-mail.
·Some ideas
for future works. (the same as in point 4
lower) There is topic for diploma work about comparison of objects ranks 1
with 2. A student may find the competent layer in similar type fold in
field, to collect measurements of geometrical parameters and to collect the
set of specimens. Usual strain-analysis is used for 3D ellipsoid
deformation calculation for specimens. The theoretic model and geometry of
fold in competent layer is used for ellipsoid deformation prediction.
Results of work are 1) Comparison of natural object and model, 2) Value of
deformation for specimens and fold. Let me
know about your interest.
*: yak@ifz.ru
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Fig. 1 (to right). There is the model of
intra-layer strain in similar folds. Competent layer is deforming by
multi-iteration calculations of 1) buckling (rotation for a flank) and 2)
flattening (the same value for all 4 cases). Results are shown in cases 1
and 3 (K1 and K3) as ellipses and its orientations. The incompetent layer
is deforming by multi-iteration of 1) “rotation and simple shearing along
bedding” as analogy of buckling and 2) flattening. Results are shown in
cases 2 and 4 (K2 and K4).
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Fig. 1. The model of
intra-layer strain in similar folds. Total shortening value for the fold is
Ê=0.396; ellipses shortening values are Ê1=0.643, Ê2=0.286, Ê3=0.668, Ê4=0.251;
a1=61.4°, a2=–59.8°, a3=–69.8°, a4=78.7°; see also the explanation of model on
left.
1 – competent layer;
2 – incompetent layer; 3 – axial plain
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